1 Watt PLL FM Broadcast Transmitter - This is a 1 Watt PLL FM broadcast transmitter. The RF output varies from 500mW to about 1.2W depending on the frequency selected and RF output transistor used. Motorola 2N4427 always seems to work well. Transmitter uses CMOS
PLL VCO that prevents the frequency drifts. The frequency is selected via DIP switches. The transmitter is supplied by 12V DC and can also be powered from the battery. __

1.5 GHz PLL Frequency Synthesizer - In order to obtain excellent phase stability between two beams in our experiment, it is preferable to derive them from the same laser. This is a limitation however, if the beams operate at different frequencies. For frequency differences of less than a few hunder MHz, the approach is to split the beam and send it through an AOM. __

19 KHz MPX Low Pass Filter - This map, armored also enables automatic MONO / MPX through a low-pass filter, even with a multiplex on its entry by using an ON / ON, panning, the whole spectrum MPX more RDS is sent to the synthesizer, on the other hand when it is in a position MONO, the low-pass filter is activated and share its cutoff frequency at 15 KHz, only modulation G + D is sent to the synthesizer, as 19 KHz. __

1W PLL Transmitter with MC145152 - Following 1W PLL transmitter exciter provides stable, low noise operation. Transmitter uses a PLL frequency synthesizer built with MC145152 which covers the FM band in 100kHz steps. The VCO uses MV2109 varicap diode to automatically tune to selected frequency via SW1 dip switch. output stage uses 2N4417 RF power transistor and provides 1W of RF power. With good antenna expected transmission range is 2km. Transmitter may be built on a double sided PCB, with top side copper left mostly undisturbed as a ground plane. The copper is removed only around non-grounded pins. The ground connections can be soldered on the top side, so itís not necessary to have plated-through holes. __

1W Portable PLL transmitter - This small FM transmitter includes a limiter, a microphone amplifier and a PLL digital tuning. All the parts are placed on one circuit board. The RF power is switchable between 1W and 0, 2W __ Jan Kolar

500mW PLL FM Transmitter 88-108MHz - This PLL transmitter is controlled and the frequency is very stable and can be programmed digitally. Transmitter will work 88-108 MHz and output power up to 500mW. With a small change can set the frequency of 50-150 MHz. The output power is often set to several watts with transistors. So therefore I decided to build a simple transmitter with great performances. The frequency of this transmitter can easily be changed by software and space / compress air coil. This transmitter is the oscillator colpitts. Oscillator is a VCO (voltage controlled oscillator) which is set by the PLL circuit and PIC micro controller. This oscillator is called the Colpitts oscillator and voltage controlled to achieve the FM (frequency modulation) and PLL control. __

8W PLL Stereo Transmitter with LCD - Very stable FM transmitter based on TSA5511 synthesizer. Frequency is performed with three buttons through PIC16F84 microcontroller. Frequency is displayed on 16x1 LCD. __

Add a door-chime repeater - 05/13/99 EDN-Design Ideas Electromechanical door chimes can enhance your home, but they are vulnerable to costly repair problems. A defective pushbutton switch or a careless visitor can maintain the chime in an energized state for a prolonged period, thereby damaging the chime. The circuit in Figure 1 prevents damage to the chime and improves the chime's effectiveness by repeating the chime strike for as long as the pushbutton remains depressed. The circuit controls both front and rear chimes. The heart of the circuit is timer IC2, which you configure as an astable multivibrator. The timing components, R1, R2, R3, and C3, provide the required pulse widths. __ Circuit Design by Dennis Eichenberg, Parma Heights, OH

Audio noise generator drives earphones or small speaker - This is a circuit that generates white noise, rolled-off to drive earphones or a small speaker. White noise creates is a "rushing" sound, which sounds something like air rushing by your ear (s). White noise would be flat with frequency, and since this circuit rolls off within the audio range, I refer to it as "rolled-off" noise. White (or rolled-off) noise __ Designed by Dick Cappels

AVR ATMega8 board for PLL MC145170 - This board allow to manage a FM transmitter including a Phase Locked Loop (PLL) on a serial bus (SPI) like a MC145170. A current frequency is memorized in EEPROM to configure PLL at power up. Three auxiliairy frequencies are available for maintenance function and/or HF adjust. A local interface include 4 keys and a LCD display enable to modify transmitter parameters. This board can be completely drived from a serial link RS232 (19200 Bds, 8b data, 2b stop, no parity). A temperature sensor enable to control working temperature and 2 analog input are used for HF power measure (Forward and Reflected). Information about TOS protection activation is processed by this board to inform user (local and remote) on a TOS Alarm. __

Barker Code-Locked Loop Synchronous Demodulator - A simple, low component count phase locked loop that locks onto and detects the amplitude of an incoming base band 7 bit Barker code using a switched resistor demodulator that is driven directly by a microcontroller's output pins __ Designed by Dick Cappels

BH1417 PLL Stereo Transmitter - This is the latest BH1417 FM Transmitter design from RHOM that includes a lot of features in one small package. It comes with pre-emphasis, limiter, stereo encoder, low pass filter, PLL rock solid frequency transmission and RF output buffer. __

BH1417 Stereo PLL FM Transmitter - The new FM Stereo Micromitter is now crystal-locked which means that the unit does not drift off frequency over time. In addition, the distortion, stereo separation, signal-to-noise ratio and stereo locking are much improved on this new unit compared to the earlier designs. The specifications panel has further details___ SiliconChip

BIAS COMS PLL transmitter - This schematic originally comes from Bias Comms and was originally intended for use in combination with a BGY33 or BGY133 module. The PLL is very straightforward and should not be too difficult to build. __

Clock multiplier circumvents PLL - 05/13/99 EDN-Design Ideas Using a standard PLL circuit, such as the CMOS
4046B with some passive components, is a wellknown way to design a clock multiplier. Unfortunately, using a PLL in a digital circuit has two disadvantages: It takesPDF contains many circuits, scroll to find this one. [Jose Carlos Cossio, Santander, Spain]circuit has two disadvantages: It takesPDF contains many circuits, scroll to find this one. __ Circuit Design by Jose Carlos Cossio, Santander, Spain